Until recently, models of human information processing focused either on structural stages of information transformation or on regulation of a limited capacity to process information. Capacity was generally a hypothetical variable although a few authors equated capacity with physiological arousal. Generally, however, energetic (motivation-al-affective) influences were not well developed. Given this, information processing concepts have had minimal impact on mental health research. Refinements in psychophysiology and a broadening of outlook in cognitive psychology has recently led to the development of models that integrate cognitive (structural) and energetic function. The current proposal examines the integration of cardiovascular functions with different information processes. Information processes can be accessed using reaction time (RT) techniques. The milliseconds time frame of RT has not permitted direct assessment of cardiovascular support during information processing. Recent studies of cardiac cycle time effects show, however, that cardiac responses to an event can be detected in a milliseconds time frame. Cardiac cycle time effects refer to changes in physiological response induced by placing events at different times relative to the P wave of the electrocardiogram. We propose to perform parametric studies of two cardiac cycle effects. Using these results, we will ask whether vascular support to muscle required by the task is similarly related to cardiac cycle. Finally, both cardiac and vascular responses will be related to stimulus evaluation and response preparation processes using a combined cardiac cycle-RT paradigm. The results should establish the degree to which cardiovascular support is an integral part of these information processes. The techniques and concepts developed should have application to the understanding of deficits in cognitive-energetic function seen in attentional dysfunction in children, certain aspects of adult mental illness, and coping with stress in normal individuals.